Snow plow mounted on chassis with one connection being an extensible strut



v 1964 R. E. WALKER ETAL 3,160,955

SNOW PLOW MOUNTED ON CHASSIS WITH ONE CONNECTION BEING AN EXTENSIBLE STRUT Filed Nov. 26, 1962 2 Sheets-Sheet 1 INVENTORS.

1964 R. E. WALKER ETAL 3,160,965

' SNOW PLOW MOUNTED ON CHASSIS WITH ONE CONNECTION BEING AN EXTENSIBLE STRUT 2 Sheets-Sheet 2 Filed NOV. 26, 1962 IINVENTORSQ P004440 E. nm/(Ee. BY flE/MX c. Jail/V50,

MQL

. on encountering such minor obstacles.

United States Patent 3,160,965 SNUW PLQW MUUNTED UN CEIASRIS WITH @NE UGNNEIZTIUN RIDING AN EXTENL fiBIE STRUT 7 Ronald E. Walker, Riverside, Ontario, Qanada, and Henry C. Johnson, Bloomiicid Hills, Mich, assignors to Phil Wood Industries, Ltd, Windsor, Gntario, anada, a corporation of Canada Filed Nov. 26, i962, Ser. No. 2393M 8 Claims. (til. Ki -42:)

This invention relates to snow plows and, in particular to snow plows which move upward to avoid obstacles in the road bed.

Hitherto, snow plows have been mounted upon preloaded coil springs which are yieldable vertically to prevent damage to the plow, its related parts or to the vehicle upon encountering a major obstacle in the pavement or on the road surface yet which otherwise hold the snow plow downward against the roadbed so as to shear olf or dislodge minor obstacles which are insufficiently resistant to cause damage." This is intended to prevent jumping up and down of the mold board up- In such spring opposed snow plows, however, as the mold board moves upward upon encountering a major obstacle, the springs do not completely release their force, but exert an ever increasing pull upon the mold board as they become extended, with the result that they slam the mold board back into position hard against the road bed. There it acts somewhat like an ice skate blade, sometimes causing the entire vehicle to skid into the path of oncoming traflic, resulting in serious damage or breakage. The present invention eliminates such damage by accurately controlling the bouncing of the mold board, eliminating the necessity for the use of such heavy preloaded springs and completely releasing when a major obstacle is encountered, thereafter controlling the travel of the plow and restoring the plow to its normal position in a much safer manner than heretofore.

Accordingly, one object of the present invention is to provide a snow plow wherein the mold board is mounted for upward travel but is held against performing such travel by a separable or extensible link or strut which remains inseparable upon encountering minor obstacles in the road bed which are capable of being dislodged or sheared off by the mold board without damage, but which automatically separates or extends upon encountering a major obstacle which otters excessive resistance as otherwise to cause damage to the mold board, the separation or extension of the parts of the link or strut enabling the mold board to move substantially freely upward, opposed by a slight spring which merely exerts pressure enough or tension enough to automatically restore the mold board to its lowered or plowing position.

Another object is to provide a snow plow of the foregoing character wherein the mold board is mounted uponroad-engaging shoes or runners connectedto it by toggle levers which permit it ,to move quickly upward upon encountering the obstacle but which upon passing over the obstacle kick the mold board assembly downward to its lowered or plowing position, thereby providing a quick return motion to the mold board.

Another object is to provide a snow plow of the foregoing character wherein the separable or extensible link or strut is equipped with a yieldingly-urged or springloaded detent which normally holds the parts of the linker strut against separation or extension, but which permits such separation or extension instantly upon encounter with a major obstacle, whereupon the force transmitted from the mold board in response to such encounter exceeds the holding force exerted by the detent 3,l,%5 Patented Dec. 15, 1964 tion along the line 1-1 in FIGURE 3, of a snow plow with the mold board in its lowered or plowing position with the separable link closed or contracted;

FIGURE 2 is a view similar to FIGURE 1, but with the mold board moved upward to pass over a major road bed obstacle, with the separable link or strut open or extended;

FIGURE 3 is a top plan View of the snow plow of FIGURES 1 and 2, mounted upon the front of a selfpropelled vehicle, such as a motor truck;

FIGURE 4 is an enlarged approximately vertical longitudinal section through the separable or extensible link or strut, taken along the line 44 in FIGURE 3; and 1 FIGURE 5 is a cross-section through the detent portion of the link or strut, taken along the line 5-5 in FIGURE 4.

Referring to the drawings in detail, FIGURES l to 3 inclusive show a snow plow, generally designated 10, according to the present invention as consisting generally of a chassis or supporting structure 12 upon which is mounted for vertical yielding movement a mold board structure 14 by a pair of rigid or inseparable laterallyspaced pivoted links 16 between which is a separable or extensible pivoted link or extensible strut device 18, the structures 12 and 14 being urged toward one another by relatively light tension springs 26, and additionally interconnected by a pair of bentlevers or toggle levers 22 carrying ground-engaging shoes or runners 24. For simplicity of illustration and easier understanding, the chassis 122 is shown as connected directly by parallel push bars 26 and pivot bolts 28 to brackets 30 (FIGURE 3), which in turn are bolted or otherwise secured to a bump- .er bar or attachment bar 32 mounted on frame members 34 projecting forwardly from the frame of a self-propelled vehicle 36, such as a motor truck. In actual practice, however, a conventional so-called lift harness (not shown) is interposed between the push bars 26 and the bar 32 and mounted upon the front of the vehicle 36 for raising and lowering the snow plow If bodily while the propelling vehicle is proceeding along the highway to and from the plowing location. Since this lift harness has no direct relationship with the plowing action of the present invention and since such lift harnesses are well known in the snow plow and road machinery art,

. it has therefore been omitted from the drawing. It will be understood, however, that any conventional lift harness may be so employed, if desired. Such a conventional lift harness is shown, for example, in United States Patent No. 1,957,103, issued May 1, 1934, to Frink for Snow Plows. v

The chassis 12 besides the push bars 26 includes rearward and forward cross members 38 and 40 (FIGURE 3) interconnected by approximately parallel hollow longitudinal box-section members 44 and 46 of roughly triangular shape both in side elevation and in top plan view. These are built-up weldments of unequal lengths welded or otherwise secured to the cross members 38 and 4t and thereby position the forward cross member 40 at an oblique angle tovthe cross member 38 and to the longitudinal members 44 and 46, which are in turn pivoted at 42 to the forward ends of the push bars 2d.

Also interconnecting the cross members 38 and 40 is an intermediate angle member 48 likewise having its opposite ends welded or otherwise secured to the cross members 38 and 40 in a position substantially perpendicular to the cross member 40 but at an acute angle to the cross member 38. Parallel to this is a second intermediate angle member 50 welded to cross member 40 and longitudinal member 46. Reinforcing plates 52 are welded or otherwise secured to the drawbars 26.

Welded or otherwise secured to the inner sides of the longitudinal members 44 and 46 are two bent brackets 54 connected to the pivot pins or bolts 42. The longitudinal members 44 and 46 are interconnected at their rearward ends by an upper rearward cross angle bar 58, a lower channel cross bar 60, and a vertical cross plate 62. The upper and lower cross bars 58 and 60 and the interconnecting plate 62 collectively form the cross member 38. The vertical cross plate 62 is vertically slotted (not shown) for the passage of the push bars 26 and to provide clearance for their rise and fall.

Secured to the front flange of the oblique angle cross member 40 are laterally-spaced forwardly-projecting ears 64 to which are pivoted three sets of paired links 66 (FIGURE 3). The opposite ends of the paired links 66 are pivoted to cars or ribs 68 secured to the back of the mold board structure 14. The nearest set of links 66 has been omitted in FIGURES 2 and 3 behind the section plane, in order to more clearly show the toggle levers 22. The ribs 68 extend between and are welded at their upper and lower ends to upper and lower angle cross members 70 and 72 respectively. The mold board structure 14 is also strengthened by curved brace bars 74, 76 and 78 of inverted J-shaped form welded or otherwise secured at their rearward lower portions to the cross members 70 and 72 and curving over the top of the mold board 80 which is correspondingly curved to deflect the snow from the plowing blade 82 upwardly and laterally from the small end 84 closed by the endplate 86 to the larger open end 88 which discharges the snow toward the side of the road. The curved bars 76 and 78 are additionally interconnected by an angle bar 90 while at the top a reinforcing bar 92 extends lengthwise of the mold board structure 14.

The blade 82 is welded or otherwisee secured to the mold board 80 and is inclined upwardly and rearwardly so as to deflect the snow in that direction against the mold board 80. The mold board 80 and the longitudinal members 44 and 46 are provided with ears 94 and 96 respectively to which the opposite ends of the inclined rigid links 16 are pivotally connected as at 95 and 97 respectively. The upper ends of the tension springs 20 are secured as at 98 to the ears 94 and extend downwardly in a more nearly vertical direction than the inclined rigid links 16 to anchorage eyes 100 upon the longitudinal members 44 and 46.

The toggle levers 22 are in the form of paired bent levers with their forward or inner ends pivoted at 99 to the ribs 68, with their intermediate portions pivoted at 181 to ears 102 welded or otherwise secured to the oblique cross member 40 in a forwardly-projecting direction, and with their lower ends pivoted at 183 to the shoes 24 which thereby rock relatively to the toggle levers 22. The toggle levers 22 are in the approximate shape of bellcrank levers with their arm portions adjacent the ears 102 disposed approximately at right angles to one another but with the lower portions of their lower arms bent downwardly toward the shoes 24.

The separable or extensible link 18 interconnecting the chassis 12 and mold board structure 14 is pivotally connected at 104 at its upper end to ears 106 welded to the mold board structure 14 and at 108 at its lower end to ears 110 welded or otherwise secured to the oblique cross member 40. The separable or extensible link or strut 18 includes an upper tubular part 112 having a cross bushing 114 welded or otherwise secured in its upper end to receive the pivot element 184, such as a pivot bolt, and having welded to its lower end a triangular block 116 (FIGURES 4 and 5). The block 116 is counterbored to receive the lower end of the upper tubular part 112 and is bored as at 118 coaxial therewith to slidably receive the solid lower link part 120 which is in the form of a solid rod slidably received within the upper tubular part 112 in telescoping relationship. Welded or otherwise secured transversely to the lower end of the rod 120 is a bearing bushing 122 which receives the pivot pin 108. The latter is transversely drilled at one end and held in place by a cotter pin 124.

The rod 120 intermediate its opposite ends is provided with an annular groove 126 which is engaged by three detent balls 128. Each of the three detent balls 128 is reciprocably mounted in a bore 130, the three bores 130 being spaced circumferentially apart from one another at angles of approximately 120 degrees. The detent balls 128 are urged into yielding engagement with the annular groove 126 in the rod 120 by helical compression springs 132, the opposite ends of which engage spring abutment plugs 134 threaded into the threaded outer ends of the bores 130 and carrying spring guide portions 136 projecting inwardly toward the detent balls 128. The corners of the triangular block 116 are flattened for engagement by lock nuts 138 threaded upon the outer ends of the screw plugs 134.

In the operation of the invention, let it be assumed that the snow plow It) has been connected to a propelling vehicle 36 by the pivoted push bars 26 which are designated as push bars in view of the fact that they push the snow plow 10 ahead of the propelling vehicle 36 rather than pull it, as in the case of a tractor pulling a farm plow by a drawbar attachment. The plow 10 normally occupies the position shown in FIGURE 1, and as it is pushed forward over the road bed R, slidably supported on its rocking shoes or runners, it rises and falls on the bars 26 as it goes over humps in the road R. The blade 82 meanwhile scoops up the snow and with the aid of the mold board 14 ejects the snow to the right out the open large end thereof to the road side. The end plate 86 at the small end of the mold board structure 14 prevents the snow from being ejected from the small end of the mold board structure 14 which thus acts as a tapered scoop. As long as obstacles in the road bed R are minor, such as pieces of ice, bricks or loose objects which may be sheared or dislodged, the separable or extensible link or strut 18 remains in its closed or contracted position, and

' the operation of the snow plow 10 proceeds normally.

If, however, the blade 82 of the snow plow 10 encounters a major obstacle 0 (FIGURE 2), the blade 82 is thrown sharply upward by it, likewise throwing the mold board structure 14 upward, and tilting the latter around the bent levers or toggle levers 22 with the levers 22 swinging toward more nearly vertical positions.

At the same time, in order to permit rapid and almost instantaneous upward displacement of the mold board structure 14 relatively to the chassis 12 and shoes 24, the upper part 112 of the extensible link or strut 18 is pulled upward along with the mold board structure 14 (FIG- URE 2), the excessive force so required jerking the grooved portion 126 (FIGURE 4) of the lower link part or rod away from its engagement with the detent balls 128, which yield rearwardly against their springs 132 to permit such separation. As a result, the overall length of the extensible link or strut 18 between the pivot elements 104 and 108 increases, and the mold board structure 14 is permitted to swing upward so that the blade 82 rides over the obstacle 0.

Immediately after the blade 82 rides over the obstacle 0 (FIGURE 2), it is followed at once by the shoe 24 immediately behind it. As the shoe 24 rides over the obstacle 0, its upward motion rotates one or both of the toggle levers 22 in a clockwise direction, so as to sharply impel the mold board structure 14 and its blade 82 down- 55 ward, increasing the action which would otherwise result only from the force of gravity acting upon its Weight.

This action of the shoes 24 and toggle levers 22 may thus be said to kick the mold board 1.4 and its blade 82 downward after passing over the obstacle 0.

When the obstacle O has been passed over, the tension springs 2t? pull the mold board structure 14 backward and downward toward the chassis 123 in such a manner as to pull the upper and lower parts 112 and 121 of the extensible link or strut 18 together or toward one another so that the detent balls 128 re-enter the annular groove 126 (FIGURE 4) and are held therein by the force of their loading springs 132 until a further major obstacle is encountered, which requires another extension action of the extensible link or strut 18.

From PTGURES 4 and 5 it will be seen that the pressures exerted by the springs 132 upon the detent balls 123, and therefore the force required to extend the link 18, may be adjusted by screwing the screw plugs 134 inward or outward (FIGURE 5) at er loosening the lock nuts 13? and retightening them after such adjustment has been completed.

What we claim is:

1. A snow plow, comprising a chassis structure,

means for connecting said chassis structure to a propelling vehicle,

supporting levers pivotally mounted on said chassis structure in laterally-spaced relationship,

roadbed shoes pivotally mounted on the lower portions of said levers,

a mold board structure having its lower portion pivotally mounted on the upper portions of said levers,

an extensible strut device connected between the upper portion of said mold board structure and said chassis structure and responsive to the imposition of a predetermined force thereon resulting from the encountering of a major obstacle by said mold board a structure to extend and thereby permit temporary upward displacement of said mold board structure over said obstacle and relatively to said chassis structure,

links means pivotally connecting the upper portion of said mold board structure to portions of said chassis rearwardly of the pivotal connections thereto of said extensible strut device and of said supporting levers, and means connected to said mold board structure for resisting said upward displacement thereof.

2. A snow plow, according to claim 1, wherein said upward displacement resisting means includes tension spring means connected between said mold board structure and said chassis structure and urging the extensible parts of said strut device toward one another into a closed position. v

3. A snow plow, according to claim 1, wherein a plurality of yielding detent devices are interposed between the extensible parts of said extensible strut device at circumferentially-spaced locations therearound in thrust-balancing relationship with one another and releasably locking the same in retracted engagement with one another, said detent devices being selectively adjustable from full-release force to no-release force.

4. A snow plow, according to claim 3, wherein one of the extensible parts of said strut device has a recess means thercaround with diverging opposite side Walls and wherein said adjustable detent devices include spring-loaded plungers having contact ends with converging opposite sides releasably engaging said recess means in said one extensible part of said strut device and connected to the other extensible part thereof.

5. A snow plow, according to claim 1, wherein said link means includes a pair of laterally-spaced links, and wherein said extensible strut device is disposed between said links.

6. A snow plow, according to claim 1, wherein said extensible strut device is connected to said chassis structure at a location forward of the connection of said link means to said chassis structure.

7. A snow plow, according to claim 1, wherein said chassis structure includes a cross member disposed obliquely to the path of travel of said chassis and wherein said levers, said link means and said strut device are also disposed obliquely to the longitudinal axis of said chassis.

8. A snow plow, according to claim 1, wherein said supporting levers are bent levers in which the pivotal mountings and connections are disposed respectively intermediate their opposite ends to said chassis structure, near their upper ends to said mold board structure, and near their lower ends to said shoes.

References tilted by the Examiner UNETED STATES PATENTS BENEAMIN HERSH, Primary Examiner. 

1. A SNOW PLOW, COMPRISING A CHASSIS STRUCTURE, MEANS FOR CONNECTING SAID CHASSIS STRUCTURE TO A PROPELLING VEHICLE, SUPPORTING LEVERS PIVOTALLY MOUNTED ON SAID CHASSIS STRUCTURE IN LATERALLY-SPACED RELATIONSHIP, ROADBED SHOES PIVOTALLY MOUNTED ON THE LOWER PORTIONS OF SAID LEVERS, A MOLD BOARD STRUCTURE HAVING ITS LOWER PORTION PIVOTALLY MOUNTED ON THE UPPER PORTIONS OF SAID LEVERS, AN EXTENSIBLE STRUT DEVICE CONNECTED BETWEEN THE UPPER PORTION OF SAID MOLD BOARD STRUCTURE AND SAID CHASSIS STRUCTURE AND RESPONSIVE TO THE IMPOSITION OF A PREDETERMINED FORCE THEREON RESULTING FROM THE ENCOUNTERING OF A MAJOR OBSTACLE BY SAID MOLD BOARD A STRUCTURE TO EXTEND AND THEREBY PERMIT TEMPORARY UPWARD DISPLACEMENT OF SAID MOLD BOARD STRUCTURE OVER SAID OBSTACLE AND RELATIVELY TO SAID CHASSIS STRUCTURE, LINKS MEANS PIVOTALLY CONNECTING THE UPPER PORTION OF SAID MOLD BOARD STRUCTURE TO PORTIONS OF SAID CHASSIS REARWARDLY OF THE PIVOTAL CONNECTIONS THERETO OF SAID EXTENSIBLE STRUT DEVICE AND OF SAID SUPPORTING LEVERS, AND MEANS CONNECTED TO SAID MOLD BOARD STRUCTURE FOR RESISTING SAID UPWARD DISPLACEMENT THEREOF. 